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LANDSLIDE DISASTER IN COLOMBIA May 18, 2015. A PRIMER OF KNOWLEDGE THAT CAN MULTIPLY AND SPILL. Walter Hays, Global Alliance for Disaster Reduction, Vienna, Virginia, USA . LANDSLIDE IN COLOMBIA.
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LANDSLIDE DISASTER IN COLOMBIAMay 18, 2015 A PRIMER OF KNOWLEDGE THAT CAN MULTIPLY AND SPILL Walter Hays, Global Alliance for Disaster Reduction, Vienna, Virginia, USA
LANDSLIDE IN COLOMBIA • The landslide occurred in the municipality of Salgar, Colombia, about 60 miles (100 kilometers) southwest of Medellin, President Juan Manuel Santos said. • Rescuers are searching for survivors, he said, but it isn't clear yet how many people are missing.
LANDSLIDE IN COLOMBIA • “Heavy rains in northwest Colombia caused the landslide at 03:00 am local time just before dawn on Monday morning while people were sleeping, killing at least 62 people, injuring at least 37, and leaving many physical and emotional healthcare problems”
A river of mud and water overran roads and bridges and crashed into homes, practically wiping the small town of Santa Margarita off the map.
Note: Photographs are used solely for educational purposes without any financial benefit.
LEADERSHIP • President Juan Manuel Santos flew over the affected area and met with local officials. • "No one can bring the deceased back to you, that is something we deeply regret, but we have to get through this disaster and look to the future with bravery and strength," he said.
LANDSLIDES represent permanent deformation caused by the downward and outward movements of large volumes of soil and/or rock down slope under the influence of the force of gravity.
PHYSICS OF LANDSLIDES • Landslides occur naturally. • Landslides can be triggered and/or exacerbated by: 1) Water (from precipitation during a tropical storm, hurricane, or typhoon), or 2) Vibrations (from ground shaking during an earthquake. • These phenomena either reduce the friction or increase the force on the slope:
LANDSLIDE HAZARDS(AKA POTENTIAL DISASTER AGENTS) • DOWN-SLOPE MOVEMENT OF SOIL AND/OR ROCK (CAN FORM AN “EARTHQUAKE LAKE”) • DOWN-SLOPE FLOW OF WET SOIL (AKA: MUDFLOW; CAN BURY A VILLAGE) • LATERAL SPREADING OF SOIL AND/OR ROCK (CAN DAMAGE INFRA-STRUCTURE)
HAZARD MAPS • INVENTORY • VULNERABILITY • LOCATION • PREVENTION/MITIGATION • PREPAREDNESS • EMERGENCY RESPONSE • RECOVERY and • RECONSTRUCTION RISK ASSESSMENT POLICY OPTIONS ACCEPTABLE RISK RISK UNACCEPTABLE RISK LANDSLIDE DISASTER RISK REDUCTION DATA BASES AND INFORMATION COMMUNITY HAZARDS: GROUND SHAKING GROUND FAILURE SURFACE FAULTING TECTONIC DEFORMATION TSUNAMI RUN UP AFTERSHOCKS
PLANET EARTH HAS THOUSANDS OF LARGE-VOLUME “LANDSLIDE LABORATORIES” EACH LANDSLIDE PROVIDES VALUABLE LESSONS ON DISASTER RISK REDUCTION
HAZARDS EXPOSURE VULNERABILITY LOCATION ELEMENTS OF RISK RISK
CAUSES OF DAMAGE SITING AND BUILDING ON UNSTABLE SLOPES SOIL AND ROCK SUCEPTIBLE TO FALLS SOIL AND ROCK SUCEPTIBLE TO TOPPLES SOIL AND ROCK SUCEPTIBLE TO SPREADS LANDSLIDES SOIL AND ROCK SUSCEPTIBLE TO FLOWS CASE HISTORIES PRECIPITATION THAT TRIGGERS SLOPE FAILURE SHAKING GROUND SHAKING THAT TRIGGERS SLOPE FAILURE
WORST LANDSLIDE: 1970 IN PERU A M7.7 earthquake that occurred offshore Peru in 1970 triggered a massive landslide of snow and rock in the Nevados Huascaran Mountains. 100 million cubic km of rock and soil buried Yungay, Ramrahirca, and several villages, killing 18,000.
EARTHQAKE TRIGGERED LANDSLIDES: BEICHUAN, CHINA, MAY 12, 2008
USE KNOWLEDGE TO ANTICIPATE LANDSLIDES: AFTER HURRICANES • HURRICANE STAN: OCTOBER 2005 • DEVASTATING MUDSLIDES WERE TRIGGERED BY PROLONGED, HEAVY PRECIPITATION.
E BUILDING ON SLOPES SLOPE FAILURE; DAMAGE LOSS OF FUNCTION ECONOMIC LOSS; DEATH & INJURY UNACCEPTABLE RISK RISK
FORECASTS OF SLOPE FAILURE MONITORING TECHNOLOGIES (E.G., REMOTE SENSING; SENSORS IN LOCAL SLIDES) WARNING SYSTEMS DATABASES FOR EACH LANDSLIDE COMPUTER MODEL OF A LANDSLIDE MAPS DISASTER SCENARIOS HAZARDS AND RISK ASSESSMENT MODELS EMERGING TECHNOLOGIES FOR LANDSLIDES
PURPOSE PREVENTION IDENTIFICATION OF SPECIFIC RISKS IDENTIFICATION OF LANDSLIDES AFTER STORMS OR EARTHQUAKES TECHNIQUE RETAINING WALLS (LOCAL SCALE) USE OF SITE-SPECIFIC DATA USE OF REMOTE SENSING FOR WARNING RISK REDUCTION STRATEGIES FOR LANDSLIDES
SITE-SPECIFIC DATA:IDENTIFICATION OF SPECIFIC RISKS • INTEGRATION OF SITE-SPECIFIC GEOLOGIC AND ENGINEERING DATA DURING CON-STRUCTION OF A HIGHWAY CAN PREVENT LOSS OF FUNCTION FROM LANDSLIDES.
SITE-SPECIFIC DATA: IDENTIFICATION OF SPECIIC RISKS • LOSS OF FUNCTION IS REDUCED WHEN SITE-SPECIFIC GEOLOGIC AND ENGINEERING DATA ARE WELL INTEGRATED.
IDENTIFICATION AND WARNING: REMOTE SENSING AFTER HEAVY RAINS, JULY 2007
IDENTIFICATION OF EARTHQUAKE LAKE: REMOTE SENSING, CHINA; MAY 31, 2008
PURPOSE STABALIZE HAZARDOUS SITUATIONS AVOID SPECIFIC LANDSLIDE HAZARDS TECHNIQUE SITE MODIFI-CATION MAPS OF SPECIFIC HAZARDS: LAND USE ZONING ORDINANCES RISK REDUCTION STRATEGIES FOR LANDSLIDES
PURPOSE SEARCH AND RESCUE EVACUATION TECHNIQUE COMMUNITY EMERGENCY RESPONSE PLAN COMMUNITY EVACUATION PLAN RISK REDUCTION STRATEGIES FOR LANDSLIDES
Evacuation needed! The rising lake of water behind the debris dam threatened to break through its banks and send a wall of water into the entire epicentral area. An urgent NEED FOR EVACUATION AS LANDSLIDES DAM RIVER
ONE OF 69 "QUAKE LAKES": BEI HE RIVER DAMMED BY LANDSLIDE DEBRIS
Warned by government officials, survivors in Beichuan (100 km; 60 miles south) and other towns down river evacuated as fast as possible, using every available means. THOUSANDS EVACUATE